Measles control is a public health issue in many developing nations and remains a high priority for public health officials in China. Measles occurs at elevated rates in particular regions of China, especially in select subpopulations, exceeding 450 cases per 100,000 in <1 year olds in Tianjin, China, in 2008. Because of limitations in China's public health infrastructure, control efforts for diseases like measles are often not guided by adequate epidemiological characterization nor supported by appropriate laboratory testing. While China's public health surveillance allows for a rudimentary understanding of measles transmission there, it has only incompletely informed their current, resource intensive, control efforts and to date, no published study has established the sero-prevalence of measles antibodies in their population. Experience in other countries has demonstrated that more efficient and effective control of measles in China will be dependent on the conduct of epidemiologically sound studies that better characterize the risks for acquisition and incorporate laboratory testing to permit an estimate of population-level susceptibility to disease. Building on a well-established training and research collaborative, we will conduct two complementary studies working with the Tianjin Centers for Disease Control and Prevention in Tianjin, China: 1) a case control study to determine the characteristics of those most likely to acquire measles and the settings in which disease occurs, and 2) a seroprevalence study investigating the presence of measles neutralizing antibodies in the population to better characterize disease susceptibility. The findings of these studies will initially be used to direct measles control efforts In Tianjin, one ofthe highest measles incidence locales in China. Successful control strategies based on these study results and developed in Tianjin will be disseminated throughout China's public health system by the national China CDC and therefore assist with their stated goal of measles eradication. Formal trainings in epidemiological and laboratory methods will be produced jointly with the China CDC to enhance existing Tianjin CDC and national public health infrastructure necessary to address measles and other infectious diseases. RELEVANCE: Control of measles is a high priority for Chinese public health officials. Vaccination efforts have focused on children;an important strategy that has significantly decreased disease in China. Unfortunately, it is not effective enough to eradicate measles. New and improved disease control efforts, based on the epidemiology of measles and susceptibility of individuals in China, are needed.